BACKGROUND: Obtaining accurate end-tidal carbon dioxide pressure measurements via nasal cannula poses difficulties in postanesthesia patients who are mouth breathers, including those who are obese and those with obstructive sleep apnea (OSA); a nasal cannula with an oral guide may improve measurement accuracy in these patients. The authors evaluated the accuracy of a mainstream capnometer with an oral guide nasal cannula and a sidestream capnometer with a nasal cannula that did or did not incorporate an oral guide in spontaneously breathing non-obese patients and obese patients with and without OSA during recovery from general anesthesia. METHODS: The study enrolled 20 non-obese patients (body mass index less than 30 kg/m) without OSA, 20 obese patients (body mass index greater than 35 kg/m) without OSA, and 20 obese patients with OSA. End-tidal carbon dioxide pressure was measured by using three capnometer/cannula combinations (oxygen at 4 l/min): (1) a mainstream capnometer with oral guide nasal cannula, (2) a sidestream capnometer with a nasal cannula that included an oral guide, and (3) a sidestream capnometer with a standard nasal cannula. Arterial carbon dioxide partial pressure was determined simultaneously. The major outcome was the arterial-to-end-tidal partial pressure difference with each combination. RESULTS: In non-obese patients, arterial-to-end-tidal pressure difference was 3.0 +/- 2.6 (mean +/- SD) mmHg with the mainstream capnometer, 4.9 +/- 2.3 mmHg with the sidestream capnometer and oral guide cannula, and 7.1 +/- 3.5 mmHg with the sidestream capnometer and a standard cannula (P < 0.05). In obese non-OSA patients, it was 3.9 +/- 2.6 mmHg, 6.4 +/- 3.1 mmHg, and 8.1 +/- 5.0 mmHg, respectively (P < 0.05). In obese OSA patients, it was 4.0 +/- 3.1 mmHg, 6.3 +/- 3.2 mmHg, and 8.3 +/- 4.6 mmHg, respectively (P < 0.05). CONCLUSIONS: Mainstream capnometry performed best, and an oral guide improved the performance of sidestream capnometry. Accuracy in non-obese and obese patients, with and without OSA, was similar.
BACKGROUND: Obtaining accurate end-tidal carbon dioxide pressure measurements via nasal cannula poses difficulties in postanesthesia patients who are mouth breathers, including those who are obese and those with obstructive sleep apnea (OSA); a nasal cannula with an oral guide may improve measurement accuracy in these patients. The authors evaluated the accuracy of a mainstream capnometer with an oral guide nasal cannula and a sidestream capnometer with a nasal cannula that did or did not incorporate an oral guide in spontaneously breathing non-obesepatients and obesepatients with and without OSA during recovery from general anesthesia. METHODS: The study enrolled 20 non-obesepatients (body mass index less than 30 kg/m) without OSA, 20 obesepatients (body mass index greater than 35 kg/m) without OSA, and 20 obesepatients with OSA. End-tidal carbon dioxide pressure was measured by using three capnometer/cannula combinations (oxygen at 4 l/min): (1) a mainstream capnometer with oral guide nasal cannula, (2) a sidestream capnometer with a nasal cannula that included an oral guide, and (3) a sidestream capnometer with a standard nasal cannula. Arterial carbon dioxide partial pressure was determined simultaneously. The major outcome was the arterial-to-end-tidal partial pressure difference with each combination. RESULTS: In non-obesepatients, arterial-to-end-tidal pressure difference was 3.0 +/- 2.6 (mean +/- SD) mmHg with the mainstream capnometer, 4.9 +/- 2.3 mmHg with the sidestream capnometer and oral guide cannula, and 7.1 +/- 3.5 mmHg with the sidestream capnometer and a standard cannula (P < 0.05). In obese non-OSA patients, it was 3.9 +/- 2.6 mmHg, 6.4 +/- 3.1 mmHg, and 8.1 +/- 5.0 mmHg, respectively (P < 0.05). In obese OSA patients, it was 4.0 +/- 3.1 mmHg, 6.3 +/- 3.2 mmHg, and 8.3 +/- 4.6 mmHg, respectively (P < 0.05). CONCLUSIONS: Mainstream capnometry performed best, and an oral guide improved the performance of sidestream capnometry. Accuracy in non-obese and obesepatients, with and without OSA, was similar.
Authors: Nimesh D Naik; Matthew C Hernandez; Jeff R Anderson; Erika K Ross; Martin D Zielinski; Johnathon M Aho Journal: Chest Date: 2017-05-10 Impact factor: 9.410
Authors: Richard B Berry; Rohit Budhiraja; Daniel J Gottlieb; David Gozal; Conrad Iber; Vishesh K Kapur; Carole L Marcus; Reena Mehra; Sairam Parthasarathy; Stuart F Quan; Susan Redline; Kingman P Strohl; Sally L Davidson Ward; Michelle M Tangredi Journal: J Clin Sleep Med Date: 2012-10-15 Impact factor: 4.062
Authors: Richard L Applegate; John Lenart; Mathew Malkin; Minhthy N Meineke; Silvana Qoshlli; Monica Neumann; J Paul Jacobson; Alison Kruger; Jeffrey Ching; Mohammad Hassanian; Michael Um Journal: Anesth Analg Date: 2016-04 Impact factor: 5.108